1. Field of the Invention
The present application relates to a precoding method, a base station and a computing circuit, and more particularly, to a precoding method, a base station and a computing circuit capable of enhancing a sum rate with low computation complexity.
2. Description of the Prior Art
As the fifth generation (5G) wireless networks grow, the millimeter wave (mmWave) communication system becomes a promising solution to increase network capacity. An advantage of the mmWave system is its short wavelength enables plenty of antennas to be packed in a certain physical dimension, allowing for large-scale spatial multiplexing and highly directional beamforming. A design challenge of the mmWave systems is that millimeter wave would experience severe path loss, penetration loss and rain fading as compared to the current cellular bands.
Since a number of antennas is large, it is luxurious to allocate one radio frequency (RF) chain dedicated for one antenna. Practically, a number of RF chains is less than a number of (transmit) antennas. Hybrid beamforming, partitioning the signal processing operation into digital precoding and analog precoding, is a new signal processing concept for the mmWave communication system, which can reduce the number of RF chains. To achieve good performance, designing digital precoder and analog precoder in an iterative fashion has been proposed. However, designing digital and analog precoders iteratively is too complicated.
Therefore, it is necessary to improve the prior art.